It is very important to acquire the blood pressure information of a subject in order to know about the health condition of the subject. In recent years, attempts have been made to capture the heart load and the change in hardness of the artery by acquiring the pulse wave of the subject, not limited to acquiring a systolic blood pressure value (maximum blood pressure value), a diastolic blood pressure value (minimum blood pressure value), and the like, which usability is widely recognized as a representative index of health management from the related art. The blood pressure information measurement device is a device for obtaining an index for health management based on the acquired blood pressure information, and further utilization in the field of early detection and prevention, treatment, or the like, of illnesses in the circulatory system is expected. The blood pressure information described above widely includes various information of the circulatory system such as a systolic blood pressure value, a diastolic blood pressure value, an average blood pressure value, a pulse wave, a pulse, and an AI (Augmentation Index) value.
A cuff for a blood pressure information measurement device (hereinafter also simply referred to as cuff) that includes a fluid bladder is generally used to measure the blood pressure information. The cuff refers to a band-shaped structure with an inner cavity that can be wrapped around one part of a living body, and it is used to measure the blood pressure information by injecting fluid such as gas or liquid into the inner cavity or discharging the fluid from the inner cavity to expand or contract the fluid bladder. For instance, in the blood pressure information measurement device (hereinafter also simply referred to as sphygmomanometer) for measuring the blood pressure value such as the systolic blood pressure value and the diastolic blood pressure value, the measurement of the blood pressure value is carried out by wrapping the cuff including the fluid bladder for compressing the artery around a body surface of the living body, and expanding and contracting the fluid bladder that is wrapped around the living body to capture the artery pressure pulse wave as a change in the inner pressure of the fluid bladder. The cuff used by being wrapped around the arm, in particular, is also called an arm band or a manchette.
The cuff is normally configured mainly by an air bladder serving as a fluid bladder, and a band-shaped exterior cover that includes the air bladder and that has an area fastener on the surface. The wide spread cuff conventionally has an annular form when, to an annular ring arranged at one end in a longitudinal direction of the exterior cover, the other end in the longitudinal direction of the exterior cover is inserted and folded back, where the blood pressure information can be measured by inserting the site to be measured to such annular portion of the exterior cover so that the cuff is wrapped around the site to be measured, and tightening the exterior cover and fixing it using the area fastener, so that the air bladder is wrapped around and fixed to the site to be measured (see e.g., FIG. 2 of Japanese Unexamined Utility Model Publication No. 63-56003 (patent document 1)).
However, in the above-described cuff, the reliable wrapping may not necessarily be reproduced because the wrapping operation is left to the hand of the subject. If the reliable wrapping is not reproduced, variation occurs in the measurement value and it becomes difficult to accurately and stably measure the blood pressure information.
A cuff of various configurations has been proposed so that the cuff can be reliably wrapped around the site to be measured with satisfactory reproducibility. For instance, Japanese Unexamined Patent Publication No. 2002-209858 (patent document 2) discloses a cuff having a configuration in which a core material made from a curved elastic plate called a curler is interiorly accommodated in addition to the air bladder serving as the fluid bladder. In the cuff having such curler, the air bladder is pushed against the site to be measured with an appropriate pushing force and fixed by the curler after the attachment, and hence, the reliable fixation of the air bladder with respect to the site to be measured can be reproduced.
However, the cuff including the curler is configured by a member having rigidity of a certain extent, and thus, the handling becomes difficult with respect to pushing out the curler and placing it on the site to be measured when attaching the cuff.
In order to further facilitate the attachment in the cuff including the curler, Japanese Unexamined Patent Publication No. 2006-68318 (patent document 3) discloses a configuration of a cuff that enables attachment and detachment to the site to be measured with a one-touch operation. In the cuff disclosed in Japanese Unexamined Patent Publication No. 2006-68318, an elastic member such as a bias spring or a power transmission mechanism such as a slider is incorporated inside the cuff so that the cuff can be attached to the site to be measured with satisfactory reproducibility at an optimum tightening force by the biasing force of the bias spring and the radial size of the curler can be varied in cooperation with the operation of the user, whereby the cuff can be attached or detached with the one-touch operation.
Japanese Unexamined Patent Publication No. 2007-268052 (patent document 4) describes a configuration in which a second core for curving a first core by being attached on the outer side of the sheet-like first core (curler) in an overlapped manner is incorporated inside a cuff, and a fixing mechanism similar to a ratchet mechanism is arranged in the second core so that the diameter of the second core does not increase at the time of the tightening operation, and the radial size of the second core can be varied in cooperation with the operation of the user, whereby the attachment or detachment of the cuff can be enabled in a one-touch operation.
Furthermore, Japanese Unexamined Patent Publication No. 2007-75294 (patent document 5) and International Publication Pamphlet 03/101290 (patent document 6) disclose a cuff in which a winding device including a bias spring and a winding roller is incorporated inside the cuff, where one end of a band-shaped belt member attached with an air bladder is wound by the winding device so that the cuff is attached to the site to be measured with satisfactory reproducibility at an optimum tightening force by the biasing force of the bias spring.
Patent Document 1: Japanese Unexamined Utility Model Publication No. 63-56003
Patent Document 2: Japanese Unexamined Patent Publication No. 2002-209858
Patent Document 3: Japanese Unexamined Patent Publication No. 2006-68318
Patent Document 4: Japanese Unexamined Patent Publication No. 2007-268052
Patent Document 5: Japanese Unexamined Patent Publication No. 2007-75294
Patent Document 6: International Publication Pamphlet 03/101290